If you rely heavily on your smartphone for directions or need to access it to make calls over Bluetooth, then you'll want the phone mounted somewhere at eye level.
The windshield is a good place to start.
CNET editors recommend the Parrot Minikit Smart.
For $100, this device will securely hold your phone, charge it, and provide Bluetooth speaker phone capabilities.
It is heavy so you wanna make sure that the suction cup is secure.
If the windshield mount obstructs your sight line or is too far away from you, try mounting your smartphone to your dashboard.
CNET recommends the Bracketron MobileDock for $30.
It doesn't do much more than cradle your phone, but its sticky mounting mechanism is sure to work on all hard surfaces.
If those devices fail, be sure to invest in a mapping app that gives you good voice instructions on where to turn such as MapQuest or Waze in case that phone does fall under the seat.
In San Francisco, I'm Kara Tsuboi, CNET.com for
CBS News.